Ooooooh! That sounds awesome! The fact that it was bear proof in the books, as well as being light enough to be pulled by an e bike makes me think carbon fiber and/or aluminum. Makes me wanna do some design mockups with rough sizing and structural estimates. Not artistic enough to do any of the murals on the sides with the gods but it would be fun to try to do structural theorizing.
(Not an engineer, i just like thinking through problems like this)
It's a fantastic series, very digestible too. The audiobooks would be super easy to finish in a weekend.